How to Measure Metric Oil Seals?
Metric Oil seals will usually have the sizes written on it, for example 20 40 10 written on the seal tells us it will be a 20mm Inside Diameter (ID) a 40mm Outside Diameter (OD) and 10mm Wide/Thick.
If nothing is printed on the seal you would just need to take Vernier etc and measure the ID,OD and Width.
You may also see letters on the seal, if it has TC this means it is a Double Lip (R23) seal or if SC is written on it this means a Single Lip (R21)
